The present invention relates generally to sewing machines capable of sewing sequins. More particularly, the present invention relates to a multi-head sewing machine equipped with a plurality of machine heads and capable of variably setting a sequin feed amount individually for each of the machine heads, as well as a method for setting a sequin feed amount for the sewing machine.
Example of the conventional sequin feeder apparatus is known from German Utility Model Registration No. G9209764.2, U.S. Pat. No. 5,755,168 or German Patent No. DE19538084 (corresponding to U.S. Pat. No. 5,755,168 above). Such a known sequin feeder apparatus includes a feed mechanism, which causes a strip of a multiplicity of continuously-connected sequins (or spangles) to be played out or let out from a reel, having the continuous sequin strip wound thereon, onto a supporting plate and then, through predetermined forward and rearward (i.e., advancing and retracting) movement of a feed lever, feeds the continuous sequin strip at a predetermined pitch corresponding to the size of each sequin of the strip. One sequin is sewn at a time onto a sewing workpiece while being severed from the continuous sequin strip having been fed in interlocked relation to a sewing operation by a needle bar of the sewing machine.
Further, in Japanese Patent Application Laid-open Publication No. 2004-167097 (corresponding to U.S. Pat. No. 7,082,884), there is disclosed an embroidery sewing machine which can sew a sequin onto an embroidering workpiece, such as an embroidering fabric, by mounting or attaching a sequin feeder apparatus to a machine head. So-called multi-needle head is known, which includes a needle bar case having a plurality of needle bars corresponding to various color threads and arranged to selectively position any desired one of the color threads at a predetermined needle drop location. In some cases, two sequin feeder apparatus are attached to the opposite sides of such a multi-needle head (as seen in (A) of FIG. 1), while, in other cases, one sequin feeder apparatus is attached to only one of the opposite sides of a multi-needle head (as seen in (B) or (C) of FIG. 1).
Generally, such a sequin feeder apparatus attached to a predetermined position of a needle bar case includes a cutter mechanism for severing a sequin from a continuous sequin strip, and the cutter mechanism is driven in interlocked relation to vertical (up-and-down) movement of a needle bar retained by the needle bar case. In a case where sequin feeder apparatus 2 and 3 are attached to the opposite sides of the needle base case as shown in (A) of FIG. 1, and if the plurality of needle bars arranged in a horizontal array in the needle base case of a single machine head H1 are referred to as first, second, third, . . . , and last needles in a right-to-left direction as viewed from the front, the first and last needles are used exclusively for sewing of sequins. But, in a case where the sequin feeder apparatus is attached to only the left side of the needle base case as shown in (B) of FIG. 1, the last needle is used exclusively for sewing of sequins, and in a case where the sequin feeder apparatus is attached to only the right side of the needle base case as shown in (C) of FIG. 1, the first needle is used exclusively for sewing of sequins. Here, “used exclusively for sewing of sequins” means that the needle bar or bars in question are used for driving the sequin cutter mechanism and for sewing a fed-out and severed sequin but not used for normal embroidery sewing.
Further, in the sequin feeder apparatus, a continuous-sequin-strip feed amount (or sequin feed amount) is adjustable in accordance with a pitch between the adjoining sequins of the strip, and such a feed amount (i.e., sequin feed pitch) can be set, on an operation panel of the embroidery sewing machine, individually or independently for each of left- and right-side sequin feeder apparatus. Thus, in the case where the sequin feeder apparatus are attached to the opposite sides of the machine head, the sewing machine can sew sequins of different types (different pitches) by setting sequins of different pitches (i.e., continuous sequin strips of different sizes) on the left and right sequin feeder apparatus 2 and 3, so that the sewing machine can achieve an embroidery with enhanced decorativeness.
However, it has so far been impossible to set a desired feed amount individually for each of the machine heads in the multi-head embroidery sewing machine although it has been possible to set a desired feed amount individually for each of the left and right sequin feeder apparatus. In the case of the multi-head embroidery sewing machine, every two machine heads, for example, may be grouped into a group to permit “group control” such that embroidery sewing can be performed by handling the machine heads as if every two machine heads grouped were a single machine head. For example, if every two machine heads of the embroidery sewing machine shown in (A) of FIG. 2 are grouped sequentially in the right-to-left direction as shown in (B) of FIG. 2, each of the groups G1-G5 can have an embroidery range E2, in an X (horizontal) direction, twice as great as a corresponding embroidery range E1 of a non-grouped machine head, so that one embroidery pattern can be created using two machine heads per group. Thus, assuming that each of the machine heads has nine needles, a large-size embroidery (i.e., an embroidery pattern having a dimension, in the X direction, twice as great as an ordinary embroidery pattern created by a non-grouped machine head) can be sewn with needle bar threads of a total of 18 colors.
However, in the case where the group control is performed in the aforementioned manner, the conventional technique, where a desired sequin feed amount can not be set individually for each of the machine heads, can use sequins of only two types, differing in feed pitch (size), even if the sequin feeder apparatus are attached to both of the left and right sides of each of the heads of the group. In the case where each group consists of two machine heads, for example, the group can use, at one time, sequins of only two sizes and four colors at the most because the sequins set on the feeder apparatus attached to the left and right sides of each of the heads can be of only two different sizes, although the sequins set on the left and right feeder apparatus of the head can be of four different colors.